I have four old Norman power packs, three of which haven't been used in a few years. Recently I tried to use the three inactive packs. They would power up and the ready light would come on, but they would not flash. I've been told that old Norman packs will deteriorate if they are not used. I've also been told that the capacitors can be refreshed if they are left plugged in for awhile. Does anyone know anything about this? I've contacted Norman and a few camera repair shops, but they won't tell me anything unless I ship them the packs first.

Call Holly Enterprises, they can explain the capacitor warm up process, but in simple terms, turning on the pack at the lowest possible power level and SLOWLY upping the power level over the course of HOURS to reform the caps. Do not attempt to fire them at all during this time.

ALL flash units have deterioration of the power capacitor, and all flash units -- regardless of battery powered portable or AC powered studio flash --need to have the capacitors 're-formed' at about 3 mo. or 6 mo. intervals (per manufacturer recommendation).

Also per manufacturer recommendation is the precise amount of time...
* my Metz flashes say to power on for 15 minutes every 3 months.
* My Dynalite studio flash says "When the power pack is not in use for one month or more, it is wise to periodically plug the power pack in and turn it ON for a couple of hours."
* Instructions for my 45 year old Honeywell (flash gone, still have owner manual) say to power up for 1 hour on AC, then flash 4-5 times, and do this once per month.

Simply turn on power, leave flash like that for recommended amount of time, then turn off.